The analysis of a composer's repertoire for a specific instrument offers a unique opportunity to evaluate the compositional style for that instrument. Such an examination also provides the opportunity to observe the extent to which the idiomatic qualities of the instrument influence the compositional process. This study explores background structures and syntax in Villa-Lobos's guitar music and the relationship of those structures to the idiomatic guitar figurations used in the repertory. Idiomatic figurations are shown to have, or be an integral part of, structure and that structure is consistent with the idiolect of the work. The structural significance of those idiomatic figurations is an issue in the guitar music of Villa-Lobos.
         Heitor Villa-Lobos (1887-1959) was one of the twentieth century's greatest composers for the guitar. His guitar music includes works of immense pedagogical value and works whose charms and emotional power affect all who hear or play them. Villa-Lobos combined Brazilian genres and rhythms with twentieth century tonal language to form his eclectic, innovative style. Compared with his total compositional output the guitar repertoire is small, yet, it is some of the most important music in the classical guitar repertory. His works for solo guitar are:  Suite Popular Brasileira (1908-12) — Mazurka-Choro, Schottish-Choro, Valsa-Choro, Gavota-Choro, Chorinho; Choros No. 1 (1920); Douze Études (1929); and Five Preludes (1940)

        Compositional Style and Idiomatic Device

        The most distinguishing formal feature of Villa-Lobos's solo guitar music is its clear sectional divisions. These sections are usually defined by a new texture, theme, or sometimes, variation. A most typical expression of this sectional form is vividly illustrated in works where the compelling cantabile melody is followed by a rapid fingerboard-shifting arpeggio ultimately returning to the original melody.
        Villa-Lobos’s compositional style, in general, exploits textural and timbral contrast. He uses the standard harmonies and chordal structures available to the guitar, often adding coloristic sevenths, ninths, and thirteenths. These harmonies are formed into standard progressions and are the foundation for most of the guitar works. The guitar works not based exclusively on harmonic progression explore contrapuntal textures and/or idiomatic techniques such as arpeggios, planing or slurs. The true compositional breakthroughs are established in the expressive qualities of the music and by the technically innovative manner in which the guitar is used.
        Discussing his compositional style, musicologist and Villa-Lobos biographer Lisa M. Peppercorn states “what is harsh and daring in the harmonic texture is the outcome of horizontal writing.”   Dissonant or ostensibly inexplicable harmonic passages are not so much the result of calculation but more the result of a juxtaposition of separate contrapuntal lines. It is the seamless integration of this linear style of composition within the homophonic texture that defines Villa-Lobos's mature music for guitar. Typically, the linear sections of music exploit the guitar's innate abilities.
        The unique characteristics inherent in the guitar or its performance are its idiomatic qualities. Idiomatic devices such as rasguedo, arpeggiation, planing, harmonics, slurring and open-string pedal tones—technical and timbral elements of the guitar—give the guitar its distinctive sound. We shall examine Villa-Lobos's innovative use of arpeggiation, chordal planing and open string pedal tones. Villa-Lobos's early works for guitar, heavily influenced by Brazilian popular style and traditional European dance forms, are written almost entirely in a tonal homophonic/chordal texture and infrequently use parallelism, extensive arpeggiation or the open string pedal tone. These idiomatic devices were fully developed within the later Twelve Etudes and Five Preludes and may occur in a phrase, section or even the entire work.
Open Strings
        Villa-Lobos’s use of the open strings exploits one of the guitar's most striking idiomatic qualities. The open string generally functions as a pedal and just as often the pedal functions as the only tonal center. When Villa-Lobos introduces an open string as the linear anticipation of structural chord tones, it is at first dissonant. The examples show how the open string foreshadows, then stabilizes or clarifies the tonality at the cadence. In an arpeggiated or planed texture, the open string pedal tones chief function is to stabilize and/or define the tonality. On many occasions Villa-Lobos employs more than one open string as a pedal. Open-string pedal tones are an attractive idiomatic and compositional device because they offer a seamless quality, effortless legato, harmonic perspective and connection, dissonance and variety of tone.

        Planing

        The maneuvering of a single fixed chord up and down the fingerboard, known as planing (sometimes called parallelism), is another salient feature of Villa-Lobos’s guitar music. Although Villa-Lobos’s use of the parallel diminished seventh chord and sixth chord is derived from a harmonically classical idiom, this procedure applied to triads rejects the traditional functions of harmony. Planing is particularly suited to the guitar. We simply form the chord on three, four, five, or six strings and literally slide it about the fingerboard. When less than six strings are stopped, there is the opportunity to affect a pedal with the remaining open string(s). The parallel chords may be strummed, plucked or arpeggiated. Villa-Lobos achieves maximum harmonic/tonal fluctuation by arpeggiating these parallel chords. As we shall see, his use of parallel chords is always governed by fundamental structure or grounded to fundamental harmony.

        Arpeggios

        The final idiomatic technique we shall discuss is arpeggiation. There is something intrinsically interesting about the arpeggiation of chords. An arpeggiation by its very nature creates structures through the order in which the chord tones are broken. The variety of patterns, rhythms, timbres and harmonies Villa-Lobos chose was truly innovative. Arpeggiation incorporating open string pedals, a signature of his style, is now so closely identified with a guitar sound. Arpeggios may be melodic, but it is the harmonic application that is unquestionably idiomatic. The use of arpeggiated parallel chords with open string pedal tones showcases all of our idiomatic devices. This procedure is used to great effect in the guitar music of Villa-Lobos. Let us look at some analyses and examine how these areas of arpeggiation, planing and/or open-string pedal tones conform to the music's background structure and syntax.

      Background Structure and Syntax

        Contemporary analysis concerned with pitch-oriented, melodic, tonal-atonal structures often seems inappropriate when applied to the music of Villa-Lobos, whose compositional style places equal emphasis on timbre, modality or, simply, idiomatic technique. The pitch structure analyses of Villa-Lobos's music used in this paper accept as premise Felix Salzer’s ideas regarding tonal coherence and structural hearing. They are voice-leading analyses using the graphic notational system derived from the work of Heinrich Schenker. By using those procedures as a test, and not a prefabricated means of analysis, much of Villa-Lobos's guitar music was analyzed. Where those procedures proved ineffective another type of analysis was adopted. The experiment also showed that occasionally it was enough to bend tradition and adapt an unorthodox use of voice-leading procedures. It is worth repeating that Villa-Lobos’s eclectic style of composition, timbral exploitation, and extensive integration and use of the guitar’s unique abilities does not always allow an explanation by a single analytical approach. The analyses discussed in this study reveal a variety of background structures and syntactical relationships.
        We shall first examine instances of idiomatic device employed within a phrase or as a connection between phrases. Example 1 shows a passage of parallel dominant seventh chords from Prelude 3, example 2 a voice-leading analysis of those chords. The planed chords complicate the tonality at this point. The bracketed motive derived from the opening of the prelude shown here as the pitches D-C-B harmonizied by the parallel G7-F7-E7 chords results in an obfuscation of the main harmonic structure. The temporally prominent G7 chord with its neighbor A7 chord creates the very strong possiblility that C major is tonic. Contextually, the motivic use of the descending filled-in third emphasizes the conclusion of the descent and in this case that emphasis is on the E7. The pedal tones E (open sixth string) and B (open second string) lead to, foreshadow and demand the structural dominant E7. The motives are in A minor, not C major, since they lead the D down to the B and the root G down to E—the true dominant that prepares the next section of the prelude. The parallel chords muddy the tonality while the open string pedals and motivic structure clarify it. We see that this use of planed chords is not random. Despite the surface tonal ambiguity the chords follow the syntax and structure of the motive found in the opening notes of the music and the open string pedals outline and anticipate the structural E7 harmony.
        In Prelude 1 we find a similar example of open string pedals and parallel chords and an analysis reveals a direct relationship to fundamental structure. Example 3 presents the analysis of the linear connections prolonging the first dominant area. There is dissonance and harmonic uncertainty as the voices move chromatically to the dominant chord. The analysis shows movement toward the dominant B7 and a subsequent movement to the tonic E minor. Throughout the dominant prolongation there is a constant open string B pedal. The B introduces the harmonic goal and remains until the other voices resolve. In this passage the open B string elegantly ties together the chromatic counterpoint with the harmonic progression.
 A second analysis on staff 2 shows the linear connections segmented into four basic elements —labeled w, x, y, z. These four basic melodic structures derived from the opening melody form the entire prelude. The x segment is a five-note diatonic scale, often heard in retrograde. The y segment is a filled-in third. The w segment is an arpeggio of the tonic triad and the z segment is the chromatic C-sharp-C-natural-B. The small variations and transpositions of each are marked with prime symbols (_, ", etc.). A full analysis shows that the melody provides continuity and cohesion throughout the prelude, even in the contrasting section. The same melodic structures form both the A and B sections.
        In the example above the movement to the dominant corresponds to a sequence of the y melodic segment which provides the line with direction as it moves through the melodic A, G, and F-sharp. The motion to the last note of the filled-in third is consistent with the other appearances of the y segment. In this case the harmony resolves on the second inversion dominant-seventh chord providing additional closure to the phrase. The B pedal tone, a foreshadowing of the dominant, solidifies that closure. The root position B7 chord begins the move to the tonic immediately after and that movement corresponds to the retrograde x segment.
        Examples 4 and 5 show two more dominant prolongations from Prelude 1. Both of these prolongations involve planing chords—example 4 is one of parallel diminished seventh chords and example 5 is of parallel major chords. Below each is a melodic analysis that reveals that each section of planed chords has as its basis the melodic segment labeled x. This is hardly an arbitrary arrangement of chords. For a composer whose music often sounds improvisational, the melodic cohesion and interconnection between harmony and melody are exceptional.
        So far we have observed phrases prolonged by parallel chords and pedal tones. In each instance the background structure of the planing corresponded to a melodic background structure and the pedal tones clarified the tonality. There is a direct relationship between idiomatic device and background structure. The implementation and exploitation of guitar techniques is inextricably bound to compositional development and musical concerns. The examples have shown this on a phrase level, we continue with idiomatic device as the basis for a whole section of music.
        In Prelude 4 Villa-Lobos uses arpeggiation and pedal tones to form the B section. The analysis of prelude 4 is shown in example 6. A typical voice-leading, pitch structure analysis illustrates, by nature of preferred prolongation technique, triadic prolongations. The analysis on staff B bends tradition by annotating the existing graphic technique to depict the motivic use of the interval of a fourth. This motivic analysis is then reduced (staff C) to show a macro-motivic structure that is the same as the first micro-motivic structure. Specifically, the descent from E through B down to the low E, connected with the upward beam, in fact spans the same shape as each of the four lower beamed units. This micro-motivic structure is sequentially repeated. The four repetitions of the motivic structure form the first section of the three-part form.
        The arpeggiated texture of the middle section differs from the single-line melody of the opening section. A harmonic analysis shown in example 7 reveals that the new arpeggiated texture of the B section is a lengthy prolongation of an E minor triad.
        The analysis of the B section in example 8 shows different groupings of the arpeggiated structures and by reduction reveals a motivic structure syntactically similar to one that is found in the A section. This is shown isolated in example 9. The elements that so clearly mark the underlying structure of the A section are also present in the contrasting arpeggiated section. Here, then, is another example of idiomatic device exhibiting fundamental structure that is directly related to other sections of the work. In these examples we do not hear these relationships, of course, but our analyses show that they are there. Of particular interest to this study is the notion that what seems like a "really neat guitar thing" is essentially an expression of fundamental structure. We shall see this again in an examination of the arpeggiations used in Prelude 2.
 Prelude 2 also features a contrasting arpeggio section. The idiomatic formation of the arpeggiated chord shown in example 10 is always the same, that is, a major triad doubled at the octave over open string pedal tones E and B. The relationship between the chord and the pedal tones constantly changes as the set formation traverses the fingerboard. The arpeggiation accentuates the difference between the pedal tones and the chord. The planed major triad clashing and resolving with the E and B pedal tones, provides movement, texture, and timbral interest.
        The analysis of Prelude 2's B section in example 11 shows the bass motion in its tonal hierarchy. The tonal hierarchy exposes harmonic syntax similar to the A section. The two analyses are shown one on top of the other to make the similarities more apparent. The syntax reveals the process by which we perceive the dissonance and resolution of the parallel chords and pedal tones.
        In both preludes 4 and 2 the contrasting arpeggiated B sections were shown to be related to their A sections in a specific way. The planed chords again correspond to some internal structure of the music. Villa-Lobos's music demonstrates compositional design developed by idiomatic device. The skillful use of the guitar's timbres and techniques within the compositional design clearly influences the process. The next examples look at idiomatic figuration used throughout a complete work.
        Villa-Lobos's most consistent use of parallel chords is found in Étude 12, a study in shifting and glissandi. A second inversion minor triad shifts about the guitar’s fingerboard for nearly the entire study. A portion of this study is shown in example 12. The harmonic framework would be unrecognizable were it not for the pedal tones.
        The analysis in example 13 shows, by upward stem, the root motion of the parallel chords and, by downward stem, the pedal tone that functions as tonic. The structure and pattern formed by the planing is now clearer. The reduction illustrates the opening root structure A-C, C-B, B-A over a tonic pedal and follows it through its many sequential repetitions. This same root motion pattern continues over a dominant E pedal until a break in the planing. The planing then continues over the tonic pedal and finally cadences on an E pedal. The dominant pedal is played throughout the B section. All of the pedal tones are open strings. The significance of the pedal tones becomes clear when we realize that based on this analysis we can actually posit a fundamental harmonic structure. The fundamental structure is shown in example 14. This structure supports the assumption of all tonal structures, tonic-dominant-tonic. It is a coherent and comprehensive tonal structure as outlined by the open fifth and sixth string pedal tones.
        The one passage that separates the planed chords, shown partially in example 15, provides contrast by its single-note texture. It is a passage that melodically juxtaposes the open and closed strings. An analysis reveals that the intervallic content of the stopped strings is comprised exclusively of the intervals minor 3rd, major 2nd, and minor 2nd. Those intervals are the same as the opening root movement of the planed chords. Again we see that even in the most contrasting moments there is an underlying syntactical similarity and that those surface features employ idiomatic device, in this case the timbral juxtaposition of open and closed strings. Etude 1 provides another example of idiomatic device employed throughout a work.
        Étude 1 is an exercise in right hand arpeggios. In this study the arpeggiation pattern is constant as the left hand forms new chords or passing harmonies in each measure. The one break in the right-hand arpeggiation, the passage using slurs, is itself an arpeggiation of the tonic E minor triad. The voice-leading analysis of Étude 1 shown in example 16 is straightforward and shows the prolongation of a basic harmonic progression. The analysis on staff A showing a more fundamental structure than that displayed on staff B. The bass notes, representing one harmony per measure, are shown on staff C. This reduction highlights the prominent acoustical position of these low tones, most of which are the open string E pedal.
        The graph shows the neighbor-tone to be one of the leading factors in the prolongation of the fundamental harmonies. The neighbor-tone can be seen in the inner voices as well as the outer voices. Coinciding with the neighbor-tones of the inner voices is the pedal tone bass note. The conjunct motion of the voices and the invariance of pitch enhance the seamless quality of the arpeggio study. The bass notes, almost exclusively pedal tones, passing tones or neighbor tones, revolve around the tonic, dominant or secondary dominant. The passing tones move the music to the dominant and the E pedal tone prolongs the tonic harmony.
        The most extensive tonic prolongation occurs in measures 12-25 represented on staff C by the twelve E's in the middle of the line. Above the low E pedal are chromatically descending parallel diminished seventh chords and another E pedal two octaves higher. The E pedal tones are the guitar's first and sixth open string. In an arpeggiated texture it is conventional to let the strings ring until the harmony changes or the fingers move—open strings continue to ring until the natural decay of the sound. Here, the open strings are heard as the pitch center. The harmonically unstable diminished seventh chords are grounded by the tonic E's—the guitar's highest and lowest strings. In these textures the ringing open strings are easy to exploit. They allow Villa-Lobos to use the open strings as an anchor to a fundmental harmony while exploring more adventurous harmonic areas. The use of the double E pedal tones and the juxtaposition of open and closed strings within the planed chord formations offers an opportunity to maximize the timbral qualities of the guitar. Open strings become background structure and as we have seen Villa-Lobos uses this technique often. The combination of arpeggiation, parallelism and open string pedal tones is part and parcel of Villa-Lobos's compositional prolongation of a fundamental harmony—a fundamental harmony typically connected to an open string. The compositional connection to the idiomatic use of the guitar is unmistakeable.

        Conclusions

        We have examined the roles of arpeggiation, planing and open-string pedal tones in some of Heitor Villa-Lobos's music for solo guitar. The use of these idiomatic devices always corresponded to the music's background structure or syntax. Despite any appearance of random application of these guitar techniques there is always some fundamental structure present. Never does technical possibility overshadow musical construction. It would seem the process of composition and the guitar's idiomatic qualities are inextricably bound. Idiomatic techniques may occur within single beats, a measure, phrase, or entire section.
        Regarding Villa-Lobos's compositional style we discussed the integration of linear compositional components within a harmonic framework and that often the linear aspects of the music exploited some guitar technique. The integration of harmony, counterpoint and planing often results in dissonance or tonal ambiguity. It is usual in these instances that the guitar's open strings support and/or outline the harmonic intention. Harmonic ambiguity within a tonal setting is a striking aspect of the composer's timbral palette. We found that when Villa-Lobos introduces elements of the destination chord in the harmonies preceding it—whether dissonant or not—we are able to witness the unfolding of a harmony. Our examples always showed the anticipated tones to be open string pedal tones. In the works where idiomatic device was used in contrasting sections we always found syntactical similarity between sections. Remember, the arpeggios in the B sections of the second and fourth prelude were shown to have the same, or similar, syntax with the A sections. An analysis of the first prelude showed four melodic structures connected to all compositional and idiomatic elements of the music. We saw examples of the relationship between one of those background melodic structures and dominant harmonies prolonged by parallel chords. In works centered entirely around idiomatic device the open strings pedals were often the only link to tonality. The analyses of the planed chords of etude 12 and the arpeggios of etude 1 uncovered background structures that governed the compositional implementation of those techniques. In these few examples we have explored the use of three idiomatic techniques and the relationship of those techniques to fundamental structure. The structural significance of passages exploiting idiomatic device is an issue in this music. An examination of all the solo guitar music of Villa-Lobos consistantly finds that idiomatic device is somehow related to background structure or syntax.
        In summary, Villa-Lobos has made a truly significant contribution to the guitar literature. The integration of his compositional style with idiomatic techniques has left a profound effect on the guitar and its literature. Villa-Lobos’s use of open string pedal tones offers the opportunity for tonal stability, or centricity, even within harmonically unstable sections. The resulting harmonic tension created by these pedal tones influenced his compositional style greatly and complements the guitars’ particular affinity for both linear and harmonic composition. Villa-Lobos's use of parallel chords by themselves provides variation on melodic structure and when accompanied by an open string pedal tone harmonic/timbral interest. Planed chords are a fundamental aspect of Villa-Lobos's music and guitar playing in general. While his use of these chords might sound improvised or random there is always a direct link to some background structure or syntax. Villa-Lobos's use of arpeggiation typically exploits both open strings and parallelisms. The synthesis of these idiomatic techniques is integral to his music.
        `Understanding background structure and idiomatic device in Villa-Lobos's guitar music can not only foster a deeper appreciation of his work but can go a long way to explain the particular internal structure of that work. An internal structure often prolonged by the guitar's intrinsic qualities.